• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.331-338
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• 2013

A new reliability calculation method is proposed based on design sensitivity analysis by the finite element method for nonlinear performance constraints in the optimal design of electromagnetic devices. In the proposed method, the reliability of a given design is calculated by using the Monte Carlo simulation (MCS) method after approximating a constraint function to a linear one in the confidence interval with the help of its sensitivity information. The validity and numerical efficiency of the proposed sensitivity-assisted MCS method are investigated by comparing its numerical results with those obtained by using the conventional MCS method and the first-order reliability method for analytic functions and the TEAM Workshop Problem 22.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.893-904
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• 2013

In this paper, a Kriging metamodel-based multi-objective optimization strategy in conjunction with an NSGA-II(non-dominated sorted genetic algorithm-II) has been employed to optimize the valve-plate shape of the axial piston pump utilizing 3D CFD simulations. The optimization process for minimum pressure ripple and maximum pump efficiency is composed of two steps; (1) CFD simulation of the piston pump operation with various combination of six parameters selected based on the optimization principle, and (2) applying a multi-objective optimization approach based on the NSGA-II using the CFD data set to evaluate the Pareto front. Our exploration shows that we can choose an optimal trade-off solution combination to reach a target efficiency of the axial piston pump with minimum pressure ripple.

• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.135-143
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• 2022

As the world has implemented social distancing and telecommuting due to the spread of COVID-19, real-time streaming sessions based on routing protocols have increased dependence on the Internet due to the activation of video and voice-related content services and cloud computing. BGP is the most widely used routing protocol, and although many studies continue to improve security, there is a lack of visual analysis to determine the real-time nature of analysis and the mis-detection of algorithms. In this paper, we analyze BGP data, which are powdered as normal and abnormal, on a real-world basis, using an anomaly detection algorithm that combines statistical and post-processing statistical techniques with Rule-based techniques. In addition, we present an interactive spatio-temporal analysis plan as an intuitive visualization plan and analysis result of the algorithm with a map and Sankey Chart-based visualization technique.

• Journal of Korean Academy of Nursing
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• v.30 no.5
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• pp.1156-1169
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• 2000

The study was aimed at developing an independent hospice center model that would be best suited for Korea based on a literature review and the current status of local and international hospices. For the study, five local and six international hospice organizations were surveyed. Components of the hospice center model include philosophy, purpose, resources (workers, facilities, and equipment), allocation of resources, management, financial support and hospice team service. The following is a summary of the developed model: Philosophies for the hospice center were set as follows: based on the dignity of human life and humanism, help patients spend the rest of their days in a meaningful way and accept life positively. On the staff side, to pursue a team-oriented holistic approach to improve comfort and quality of life for terminally ill persons and their families. The hospice center should have 20 beds with single, two, and four bed rooms. The center should employ, either on a part-time or full-time basis, a center director, nurses, doctors, chaplains, social workers, pharmacists, dieticians, therapists, and volunteers. In addition, it will need an administrative staff, facility managers and nurses aides. The hospice should also be equipped with facilities for patients, their families, and team members, furnished with equipment and goods at the same level of a hospital. represented by a center director who reports to a board and an advisory committee. Also, the center director administers a steering committee and five departments, namely, Administration, Nursing Service, Social Welfare, Religious Services, and Medical Service. Furthermore, the center should be able to utilize a direct and support delivery systems. The direct delivery system allows the hospice center to receive requests from, or transfer patients to, hospitals, clinics, other hospice organizations (by type), public health centers, religious organizations, social welfare organizations, patients, and their guardians. On the other hand, the support delivery system provides a link to outside facilities of various medical suppliers. In terms of management, details were made with regards to personnel management, records, infection control, safety, supplies and quality management. For financial support, some form of medical insurance coverage for hospice services, ways to promote a donation system and fund raising were examined. Hospice team service to be provided by the hospice center was categorized into assessment, physical care, emotional care, spiritual care, bereavement service, medication, education and demonstrations, medical supplies rental, request service, volunteer service, and respite service. Based on the results, the study has drawn up the following suggestions: 1. The proposed model for a hospice center as presented in the study needs to be tested with a pilot project. 2. Studies on criteria for legal approval and license for a hospice center need to be conducted to develop policies. 3. Studies on developing a hospice charge system and hospice standards that meet local conditions in Korea need to be conducted.

• Journal of the Ergonomics Society of Korea
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• v.28 no.1
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• pp.37-51
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• 2009

The nuclear power industry in the world has recognized the importance of integrating non-technical and team skills training with the technical training given to its control room operators to reduce human errors since the Three Mile Island and Chernobyl accidents. The Nuclear power plant (NPP) industry in Korea has been also making efforts to reduce the human errors which largely have contributed to 120 nuclear reactor trips from the year 2001 to 2006. The Crew Resource Management (CRM) training was one of the efforts to reduce the human errors in the nuclear power industry. The CRM was developed as a response to new insights into the causes of aircraft accidents which followed from the introduction of flight recorders and cockpit voice recorders into modern jet aircraft. The CRM first became widely used in the commercial airline industry, but military aviation, shipboard crews, medical and surgical teams, offshore oil crews, and other high-consequence, high-risk, time-critical industry teams soon followed. This study aims to develop a CRM training program that helps to improve plant performance by reducing the number of reactor trips caused by the operators' errors in Korean NPP. The program is; firstly, based on the work we conducted to develop a human factors training from the applications to the Nuclear Power Plant; secondly, based on a number of guidelines from the current practicable literature; thirdly, focused on team skills, such as leadership, situational awareness, teamwork, and communication, which have been widely known to be critical for improving the operational performance and reducing human errors in Korean NPPs; lastly, similar to the event-based training approach that many researchers have applied in other domains: aircraft, medical operations, railroads, and offshore oilrigs. We conducted an experiment to test effectiveness of the CRM training program in a condition of simulated control room also. We found that the program made the operators' attitudes and behaviors be improved positively from the experimental results. The more implications of the finding were discussed further in detail.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.3
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• pp.121-132
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• 2020

University Students go through the development process of expertise in a single field based on theoretical knowledge they have learned in the university. Their plans to develop their careers could lead to a shift in business as they choose to find jobs and start businesses throughout their lives. The attitude of career decision making process has been changed from learning in the form of receiving and memorizing existing knowledge to learning in a more proactive and autonomous manner, and there is a growing need for informal learning. In this study, the informal learning is investigated to clarify the impact on the employment competency and entrepreneurial intention. New implications are deduced by the introduction of start-up business to the traditional approach based on the employment ability. In addition, the importance of team-work has been increased in the field of eduction and business. The impact on the employment competency and entrepreneurial intention is studied based on the satisfaction level of team-based learning. Survey was conducted on 163 university students in North Chungcheong Province from March to June 2019 and the results of the study were summarized as follows. First, it has been confirmed that the informal learning of university students has a significant impact on their employment competency, but not on their entrepreneurial intention. Second, the employment competencies have perfect mediating effect on the informal learning and the entrepreneurial intention. Third, the satisfaction on the team-based learning did not have a significant impact on the employment competency of university students by informal learning, but it had a positive effect on the dependency between employment competency and entrepreneurial intention. In these days, start-up education at universities has been strengthened. Throughout this research, the need for informal learning is confirmed to enhance the employment competency and entrepreneurial intention of the university education program. In addition, team-based learning is introduced actively to utilize a variety of information from the university students.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.153-161
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• 2008

The guidelines for indoor air quality of public transportations such as subway, train and bus was presented by Korean Ministry of Environment last end of year 2006 based on the great consequence of indoor air quality in daily life. Two main parameters, carbon dioxide($CO_2$) and particulate matters smaller than $10\;{\mu}m(PM_{10})$, were selected as index pollutants for the management of indoor air quality. The former pollutant, $CO_2$, is regarded as index of ventilation status and the major source of $CO_2$ in the train or subway is the exhalation of passengers. It is publically perceived that the high $CO_2$ concentration in a crowded subway will be reduced and ventilated with outdoor air by door-opening taken every 2 or 3 minutes when the train stops each station. However, there has not been any scientific proof and quantitative information on the effect of door-opening on the $CO_2$ reduction by ventilation with outdoor air. In this study, $CO_2$ concentration and number of passengers were measured at each station on the 3 lines of Korail metropolitan subway. In order to evaluate the effect of $CO_2$ reduction by door opening, the theoretical approach using the $CO_2$ balance equation was performed. By comparing the predicted data with monitoring one, the optimum $CO_2$ dilution factor was determined. For the first time, it was quantified that about 35% of $CO_2$ concentration in the subway indoor was removed by the door-opening at each station.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.24-30
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• 2010

In this study, numerical experiments were carried out to estimate the SCR De-NOx performance in DOC plus SCR systems. The SCR De-NOx phenomena are described by Langmuir-Hinshelwood reaction scheme. After validating the present approach by comparing the present results with the experimental results, such various parameters as space velocity, $H_2O$ concentration, $NO_2$/NOx ratio and relative volume of DOC are explored to increase the SCR De-NOx performance. The results indicate that SCR De-NOx performance largely depends on space velocity and $NO_2$/NOx ratio, especially below $200^{\circ}C$. SCR De-NOx performance is seriously affected by relative volume of DOC with SCR due to increasing in $NO_2$/NOx ratio at below $250^{\circ}C$.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.2
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• pp.127-134
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• 2017

For product or process design and development, it is common to optimize multiple responses (characteristics) based on experimental data. To determine optimal conditions, we need to design the experiment, estimate a proper model for each response, and optimize the multiple responses simultaneously. There are several techniques and many research results on optimizing multiple responses simultaneously, when the experimental data are available. However, the experimental design issue for optimizing multiple responses has not been discussed yet. This paper proposes some idea on how to plan screening design when requirements for multiple performance characteristics are to be met in developing new products. A screening design procedure is developed for securing the requirements of multiple responses. Initial design factors are classified into three categories; specific, non-conflicting common, and conflicting common. After screening experiments, follow-up design region search method is suggested with respect to the most unsatisfied or important response, or overall desirability. A case study on a synthesis of melamine formaldehyde resin is presented to illustrate the procedure and to show the validity of the approach.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.596-604
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• 2016

In this study, we used a stochastic approach for guaranteeing the reliability and robustness of the performance with regard to the design of polymer components, while taking into consideration the degradation properties and operating conditions in automobiles. Creep and tensile tests were performed for obtaining degradation properties. The Prony series, which described the viscoelastic models, were calculated to use the creep data by the Maxwell fluid model. We obtained the stress data from the frequency response analysis of the polymer components while considering the degradation properties. Limit state functions are generated by using these data. Reliability assessments are conducted under the variation of the degradation properties and area of frequency at peak response. For this study, the input parameters are assumed to be a normal distribution, and the reliability under the yield stress criteria is evaluated by using the Monte Carlo Simulation. As a result, the reliabilities, according to the three types of polymer materials in automotive components, are compared to each other and suggested the applicable possibility of polymeric materials in automobiles.